I have found that when a man reaches the advanced age of seventy-one years, as I have, the continual sight of dark clothing is likely to have a depressing effect upon him. Light colored clothing is more pleasing to the eye and enlivens the spirit. Now, of course, I cannot compel everyone to wear such clothing just for my special benefit, so I do the next best thing and wear it myself.
It was "especial" in the original source, so I kept it that way. I think that was the standard spelling at that time. Given that no one uses that spelling anymore, I agree with your edit.
I didn't know if 'especial' was supposed to be 'special'. I don't think Mark Twain was Hispanic... I also don't know if the (-) hyphen? was part of the original quote or not, it doesn't look right. (The 'Light - colored')
Otherwise, I love Mark Twain, so of course I think it's a great quote.